Common Disorders

Sesamoiditis

Sesamoid bones are commonly found in and
around joints. While sesamoid bones can be found around any joint in
the foot, they are consistently found within the joint of the great
toe. The great toe joint contains 2 sesamoid bones, the tibial and
fibular sesamoids.

The sesamoids serve 2 very
important functions based on their location: 1) they serve to protect
the large tendon to the great toe, the Flexor Hallucis Longus, which
functions to pull the toe down against the ground during gait. The
tendon courses between these two bones; 2) they also serve as a fulcrum
for the short flexor tendon, Flexor Hallucis Brevis, which attaches to
the base of the great toe. This tendon stabilizes the toe against the
ground at the push-off phase of gait and allows for effective forward
propulsion of the body.

Because of their location
and the amount of force transmitted through these bones, they are
susceptible to a variety of injuries. Additionally, certain foot
structures and activities will increase the susceptibility of these
bones. Fractures and inflammation (sesamoiditis) are quite common.
Fractures of a sesamoid bone can involve either the tibial or fibular
sesamoid. This is an actual break within the bone. Because the flexor
hallucis brevis tendon is attached to the sesamoids, there is often
displacement of the fracture, leading to a high rate of delayed healing
or even nonunion.

Sesamoiditis is an inflammatory
condition of the periosteum or bone lining of the sesamoid bone.
Typically, patients will relate a history of excessive activity as a
precursor to pain in this location. Other risk factors include:
running, jumping from a height, ballet dancing, wearing of high heels
or shoes with little cushioning and high-arched foot type. With early
and appropriate treatment, these often improve.

Diagnosis

Initial
diagnosis is made by a careful history and physical examination. Pain
localized to the bottom of the great toe joint is the typically
presentation of these types of injury. The pain can be easily localized
to either the tibial or fibular sesamoid by directly pressing on either
bone. Movement of the joint may also duplicate the patient's pain.
Occasionally, swelling and redness may also be seen depending on the
mechanism of injury. X-rays are often obtained to differentiate
sesamoiditis from a sesamoid fracture. Three different views of the
sesamoids are commonly taken. Also, when sesamoid fractures are
suspected, it is helpful to x-ray the uninvolved foot as well.
Typically, the sesamoid bones are 2 well-defined bones on x-ray. This
is the case for approximately 85% of the population. However, in 15% of
patients each sesamoid bone may consist of 2 or more fragments
(referred to as multipartite or several pieces). This will often make
the distinction between normal and fracture difficult. In this case, a
bone scan or MRI
can be helpful. It is important to differentiate between sesamoiditis
versus fracture since the treatment is dramatically different.

Treatment

The
treatment of sesamoid injuries is dependent on making a definitive
diagnosis. Because sesamoiditis is an inflammatory condition, treatment
directed at reducing inflammation is often helpful. This may include:
rest, ice, anti-inflammatory medications and physical therapy. More
resistant cases of sesamoiditis may be helped by clf muslce stretching,
a cam-walker removable cast and/or an occasional cortisone injection.
Cortisone injections should only be performed after the physician is
fairly certain a fracture does not exist.

Long-term
therapy must be geared to identifying the cause of the sesamoiditis so
as to avoid these situations or to accommodate foot deformities or
modify shoes. This may include the use of orthotic devices, calf muscle stretching, or a dorsal night splint. This may also include the limited use of high heel shoes.

Sesamoid
fractures require a more aggressive course of treatment because of the
high risk of nonunion. Cast immobilization for 6-8 weeks is the initial
treatment of choice. The patient should then be advanced gradually to
full weightbearing with a removable brace. Even in spite of appropriate
treatment, many sesamoid fractures go on to delayed or non-unions. When
conservative care has failed to render the patient pain free,
consideration to removal of the offending sesamoid should be given.
Once again, long-term therapy should be geared at identifying the cause
of the fracture and treating or modifying those activities leading to
the fracture in the first place.